The present invention relates generally to a system for controlling ignition characteristics of certain internal combustion engines, and particularly to a valve and mounting system for mounting a combustion sensor in direct communication with a cylinder of an engine.
Internal combustion engines are used in a wide variety of applications, including providing power for a variety of vehicles. Generally, such engines include one or more cylinders that each contain a piston designed for movement in a reciprocating manner. Each piston is connected to a crankshaft by a connecting rod that delivers force from the piston to the crankshaft in a manner that rotates the crankshaft. Power to drive the piston is provided by igniting an air-fuel mixture supplied to the cylinder on a side of the piston opposite the connecting rod. The air-fuel mixture is ignited by some type of ignition device, e.g. providing a spark across electrodes of a spark plug.
Air and fuel may be supplied to each cylinder by a variety of mechanisms, e.g. a fuel injection system. Regardless of how the air-fuel mixture is established, it is necessary to adjust or change the air-fuel mixture according to operating conditions. For example, application of greater throttle for increased engine speed requires a greater quantity of fuel. On the other hand, maintaining the engine operation at a lower rpm, requires a lesser quantity of fuel supplied to each cylinder. Generally, greater control over combustion conditions, e.g. air-fuel mixture, provides an engine designer with a greater ability to bring about a desired engine performance under a greater range of operating conditions.
One way of obtaining greater control over combustion conditions is by sensing combustion by-products, such as exhaust gasses. Combustion condition sensors, such as oxygen sensors, can be used to detect and analyze conditions, such as air-fuel mixture, by detecting oxygen content in the exhaust gas. Proper utilization of oxygen sensors and other types of sensors dictates that external gasses, such as outside air, do not mix with the exhaust gasses prior to sensing. Additionally, many sensors are susceptible to degradation when contacted by particles or droplets of fuel and oil that remain after combustion. Accordingly, it would be advantageous to have a sensor arrangement designed to promote accurate sensing of exhaust gasses over a long duration.
The present invention features a system for sensing a combustion condition in an internal combustion engine. The system includes an engine having a cylinder defined by a cylinder wall along which a piston moves in a reciprocal manner during operation. The system further includes a sampling passage extending through the cylinder wall into fluid communication with the cylinder. A sensor is positioned to sense a combustion condition based on an outflow through the sampling passage. The system also includes an outflow diverter to limit direct exposure of the sensor to any undesirable liquids carried by the outflow.
According to another aspect of the present invention, a system is provided for sensing a combustion condition in an internal combustion engine. The system includes an engine having a cylinder defined by a cylinder wall along which a piston moves in a reciprocal manner during operation. The system also includes a sampling passage extending through the cylinder wall and a sensor position to sense a combustion condition based on an outflow through the sampling passage. The system also includes a sensor chamber positioned about an outlet of the sampling passage. The sensor chamber is defined by a chamber wall having a drain outlet therethrough.
According to another aspect of the invention, an internal combustion engine is combined with a watercraft and a combustion condition is sensed to improve operation of the watercraft. The sensor utilizes a sampling passage extending through the cylinder wall into fluid communication of the cylinder and an outflow diverter to limit direct exposure of the sensor to any undesirable liquids carried by the outflow.